Rotary pumps

ABSTRACT

A rotary pump comprises a chamber having an inlet port and an outlet port, a rotor within the chamber, one or more rollers carried by the rotor to rotate therewith, and a closed-loop belt tightly enclosing under tension the rotor and rollers. As the rotor is rotated, the rollers move along the belt and continuously press it against the chamber wall as each roller moves from inlet port to outlet port, the belt tension maintaining intermediate free runs of the belt in substantially straight lines spaced from the chamber wall.

United States Patent Rosenberg 51 July 18,1972

1 1 ROTARY PUMPS [72] Inventor: Peretz Roanberg, Moshay Belt Sherim,

Israel [22] Filed: Aug. 17, 1970 [21] Appl. No.: 64,449

[30] Foreign Application Priority Date Sept. 9, 1969 Israel ..32970 [52] US. Cl ..418/45, 417/477 [51] Int. Cl ..F04b 43/08, F04c 17/00 [58] Field ofSearch ..418/45; 92/132;4l7/474, 475,

[56] References Cited UNITED STATES PATENTS 513,316 1/1894 Funk ..417/476 3,216,36211/1965 Hewko.... ..4l8/45X FOREIGN PATENTS OR APPLICATIONS 10/1954 Austria ..417/476 180,550 6/1922 Great Britain ..417/476 729,944 5/1955 Great Britain ..417/475 614,727 12/1948 Great Britain ..417/476 302,067 I 1/1917 Germany ..418/45 Primary ExaminerCarlton R. Croyle Assistant Examiner-R. Gluck Attorney-Benjamin J. Barish 1 ABSI'RACT A rotary pump comprises a chamber having an inlet port and an outlet port, a rotor within the chamber, one or more rollers carried by the rotor to rotate therewith, and a closed-loop belt tightly enclosing under tension the rotor and rollers. As the rotor is rotated, the rollers move along the belt and continuously press it against the chamber wall as each roller moves from inlet port to outlet port, the belt tension maintaining intermediate free runs of the belt in substantially straight lines spaced from the chamber wall.

2 Claims, I 1 Drawing Figures Patented July 18, 1972 $677,668

2 Sheets-Sheet 3 FIGS F[G 6 lnvenrsrz PERETZ ROSENBERG gm awz Arrorney ROTARY PUMPS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to rotary pumps.

2. Description of the Prior Art Many types of rotary pumps have been devised. the most common ones being the gear, lobe, screw and vane types. All or most of the known rotary pumps, however, involve friction or sealing problerm which decrease the efficiency of the pump and also limit its speed and/or size. In addition, some of the known types include eccentrically mounted rotors, which again limit the speed and/or size of the pump, as well increasing its complexity and cost.

SUMMARY OF THE PRESENT INVENTION A broad object of the present invention is to provide novel rotary pumps which may be designed and constructed to provide advantages in one or all of the above respects.

According to a broad aspect of the present invention, there is provided a rotary pump comprising a chamber having an inlet port and an outlet port, a rotor rotatably mounted within the chamber, one or more pressure elements, preferably in the form of rollers, carried by the rotor to rotate therewith, and a closed-loop belt tightly enclosing under tension the rotor and rollers. The rollers extend radially of the rotor toward the chamber wall such that as the rotor is rotated, the rollers move along the inner surface of the belt and continuously press the outer surface of the belt against the chamber wall as each roller moves from inlet port to outlet port of the chamber. Intermediate free runs of the belt, while not in contact with the rollers, are maintained in substantially straight lines spaced from the chamber wall by the belt tension.

While unidirectional valves may be included in the inlet and/or outlet ports, one of the important advantages of the invention is that these posts may be valveless, and instead, the chamber may include separating means cooperable with the belt for preventing direct or open communication between the inlet and outlet ports during operation of the pump. A number of forms of separating means are described below and constitute further features of the invention.

In the pump construction of another embodiment of the invention, the inlet and outlet ports have a common axis, and the chamber includes two rotors, one on each side of the common axis. The rotors rotate in opposite directions and each includes a plurality of equally-spaced rollers. This embodiment is analogous to spur-gear type rotary pumps.

The invention, which may be embodied in a great many dif ferent forms only some of which are illustrated herein, enables the construction of rotary pumps generally characterized by less friction, greater displacement, wider ranges of sizes and speeds, simpler construction, and/or greater efficiency, when compared to other known forms of rotary pumps.

Further features and advantages of the invention will be apparent from the description below.

BRIEF DESCRIPTION OF THE DRAWINGS.

The invention is herein described, somewhat diagrammatically and by way of example only, with reference to the accompanying drawings, wherein:

FIG. 1 illustrates one form of rotary pump constructed in accordance with the invention;

FIG. la illustrates the construction of a pressure element or roller may be used;

FIGS. 2-5 illustrate further fonns of rotary pumps constructed in accordance with the invention;

FIG. 6 illustrates a still further variation, FIGS. 6a, 6b and 6c showing different stages of operation of the pump of FIG. 6; and

FIG. 7 illustrates a still further variation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The rotary pump 2 illustrated in FIGS. 1 and 10 comprises a housing 4 formed with a chamber 6 having a peripheral wall 7 and a pair of side walls 7'. The chamber further includes an inlet port 8, and an outlet port 10. Disposed within chamber 6 is a rotor 12 having four radial am 14 each can'ying a pressure-element in the form of a roller 16. All the arms 14 are of equal length and equal spacing around rotor 12. Each roller 16 extenck radially toward the chamber peripheral wall 7 and and is of a length equal to the chamber width so that it extends completely across the chamber between its side walls 7'.

The main section 6 of chamber 6 is circular in cross-section, the chamber extending laterally of the axis I7 of inlet and outlet ports 8 and 10, and coming to an apex 6" about midway between the two ports. A pressure idler roller 18 is disposed in this latter section of the chamber and is slightly spaced from a sealing element or strip 19 located at apex 6".

A closed-loop, flexible belt 20 of the same width as chamber 6, encloses the rotor rollers 16 and the idler roller 18, the belt being tightly applied so as to be under tension.

It will be seen that as rotor 12 rotates, e.g., in the counterclockwise direction of the arrow in FIG. I, rollers 16 move along the inner surface of belt 20 and press the outer surface of the belt against the chamber peripheral wall 7 continuously during the movement of the rollers from the inlet port 8 to the outlet port 10 of chamber section 6. The free intennediate portions or runs 20' of the belt not in contact with the rollers 16 are maintained in substantially straight lines spaced from the chamber wall because of the tension of the belt. Thus, during the rotation of rotor 12, the fluid entering through inlet port 8 into the space between belt 20 and the chamber peripheral wall, will be driven by rollers 16 (acting on belt 20 which forms a seal between it and the chamber walls) counterclockwise around the circular section 6' of the pump chamber to the outlet port 10, where it will be exhausted.

In section 6" of the chamber, belt 20 passes between idler roller 18 and sealing strip 19, the latter functioning together with the belt as a separating means for preventing direct or open communication between the inlet and outlet ports during operation of the pump.

To reduce friction, the pump uses rollers 16 freely rollable on belt 20, analogous to a conventional pulley and belt ar' rangement, rather than slidable pressure elements. In FIG. la, which illustrates one manner of mounting rollers [6 on their respective arms 14, each roller is actually made of two halves 16a and 16b flush with the outside edges of the belt and contacting the opposed faces of the chamber side walls 7'v Instead of having four rollers 16 on the rotor I2, there of course could be a different number. FIG. 2 illustrates an arrangement where there are only two rollers 22 carried apart on rotor 24. The belt 26 in this embodiment tightly encloses the two rollers 22 and the idler roller 28, and passes between the latter and the sealing strip 29, corresponding to element 19 in FIG. 1. To maintain the belt tension, idler roller 28 is urged toward sealing roll 29 by a compression spring; and to reduce friction, the chamber wall carries a pair of further rolls 31 one on each side of the recess containing roll 29. In this case the belt 26 also contacts the sides 24' of the rotor between the two rollers 22, and therefore there is a greater amount of space between the intermediate free runs 26' of the belt and the chamber wall. The operation of the embodiment of FIG. 2 is otherwise the same as in FIG. 1, the counterclockwise rotation of rotor 24 causing rollers 22 to press belt 26 against the walls of the chamber and thereby to pump the fluid as the rollers move from the inlet port 32 to the outlet port 34.

The embodiment shown in FIG. 3 illustrates for purposes of example only one roller 40 on rotor 42 enclosed by belt 44. The pump chamber 46 is circular in section and includes inlet port 48 and outlet port 50. A flexible strip 52 is fixed at one end to the belt, and at the opposite end to the chamber peripheral wall at a point between the inlet and outlet ports.

Flexible strip 52 is of the same width as the belt and serves as a separator for preventing open communication between the inlet and outlet ports during operation of the pump. Flexible strip 52 will hold the belt against rotation, and therefore there will be slippage between the belt and the chamber wall. A low friction belt should therefore be used.

FIG. 4 illustrates a further variation in which there are two rollers 54 disposed on opposite sides of the rotor 56. A bowed, cantilever-mounted strip 58 carries at one end a sealing element 59 which bears against belt 60. At the opposite end, strip 58 is fixed to the chamber wall between the inlet port 62 and outlet port 64. Strip 58 is substantially of the same width as the belt and chamber, and is springy so as to urge sealing roll 59 against the belt as the rotor rotates. The chamber wall is formed with a recess 59 just before outlet port 64 to accommodate roll 59 when a roller 54 approaches the outlet port.

In the variation of FIG. 5, the pump includes two rollers 66 carried on rotor 68, both tightly enclosed by belt 70, as in the FIG. 4 arrangement. However, another form of separating means is used; and also two inlet and two outlet ports are shown for purposes of example, namely inlet port 72, outlet port 74, inlet port 76, and outlet port 78, Outlet port 74 may be connected to inlet port 76, as shown by the broken-line conduit 80 to provide for two-stage pumping of the same fluid; or the arrangement of FIG. could be used as two separate pumps, for example to pump two fluids.

The separating means in the FIG. 5 variation includes a radial plate or arm 82 seated in a recess 84 in the chamber wall between inlet 72 and outlet 78. Arm 82 is of substantially the same width as the belt and the chamber, and is biased inwardly toward the belt by a coil spring 86. The free (i.e., inner) end of the arm carries a sealing strip 88 continuously urged against the belt. Thus, as the rollers 66 roll along the belt during rotation of the rotor, arm 82 and sealing strip 88 effectively prevent open communication between inlet port 72 and outlet port 78.

The same arrangement is provided at the other side of the pump chamber, which side includes arm 82' seated in recess 84' and urged radially inwardly by spring 86 to cause sealing strip 88' to bear against the belt.

FIG. 6 illustrates a somewhat different variation. Here, the pump chamber 90 is oblong, the two ends 90' and 90" being semi-circular in section. The pump includes two rotors 92 and 94 each located at one side of the chamber and disposed on opposite sides of an axis 96 common to the inlet port 98 and the outlet port 100, axis 96 being perpendicular to the long axis of the oblong chamber. Each rotor includes two rollers, namely rollers I02 on rotor 92, and rollers I04 on rotor 94. Belt 106 is disposed under tension over these rollers.

The two rotors 92 and 94 are rotated in opposite directions and at the same speed. An external coupling, e.g., meshed gears I08 and Ill] (shown schematically in broken lines), is provided between rotors 92 and 94.

The embodiment of FIG. 6 operates somewhat analogous to a spur-gear pump. Thus, rotation of rotor 92 clockwise causes the fluid from inlet port 98 to move clockwise within side 90' of chamber 90 to the outlet port 100; and rotation of rotor 94 counter-clockwise causes the fluid to move counter-clockwise from inlet port 98 through side 90" of the chamber to the outlet port 100.

This will be clear from the diagram 6a, 6b and 6c showing the positions of the elements of the pump during difi'erent stages of operation. In FIG. 6a, rotors 92 and 94 are shown as having moved 45 from the positions shown in FIG. 6; in FIG. 6b, and in FIG. 6c, Assuming that in FIG. 6, side 90' of the chamber is filled with fluid, it will be seen that in FIG. 60 such fluid is being positively displaced by the lower roller I02 (acting on the belt 106) toward outlet 100; in FIG. 6b, it is being partly exhausted through the outlet; and in FIG. 6c, its exhaustion through the outlet is substantially completed. On the other side, 90", of the chamber, in FIG. 6 that side is being tilled with fluid from the inlet 98; in FIG. 60 it is completely filled; in FIG. 6b it is being pum d counter-clockwise in the direction of outlet 100; and in G. 6: it is about ready to be exhausted through outlet 100.

In the embodiment of FIG. 6, the closed-loop belt 106 is supported only by the rollers. Thus, as the rotors rotate to cause the rollers to press the outer surface of the belt against the chamber peripheral wall along the semi-circular end sec tions of the chamber, the two runs of the belt intersecting the common axis 96 between the inlet and outlet ports are each supported in the form of a straight line between a roller on each of the two rotors 92, 94. This arrangement obviates the need for a separator between the inlet and outlet ports required in the previously described embodiments, or an attachment between the belt and the chamber wall. It has also been found that the belt is maintained under a substantially constant tension during the rotation of the rotors, and thus a more uniform output is produced during the operation of the pump.

It is not essential that there be only two rollers on each rotor, or that the two rotors rotate out of phase with each other. For example, in FIG. 7 there is shown a rotary pump similar to that of FIG. 6, except that each of the two rotors I12 and I14 carries four rollers I16 and 118, respectively. Also, the rotors are rotated in opposite directions but in phase with each other, i.e., with the rollers of one aligning with those of the other during the rotation of the two rotors. This construction, too, is analogous to a spur-gear type rotary pump.

Many other variations, modifications and applications of the illustrated embodiments will be apparent.

What is claimed is:

l. A rotary pump comprising: an oblong chamber having a long axis the opposite ends of which are semi-circular in section; an inlet port and an outlet port having a common axis perpendicular to the long axis of the oblong chamber; two rotors one on each side of said common axis; means for rotating said rotors in opposite directions; at least two equally spaced rollers carried by each of said rotors; and a single closed-loop belt of a width equal to that of the chamber disposed within but unattached to said chamber; said closed-loop belt being supported by said rollers and tightly enclosing same while under tension; whereby rotation of the rotors causes the rollers continuously to press the outer surface of the belt against the chamber peripheral wall along semi-circular end sections of the chamber, while the two runs of the belt intersecting said common axis between the inlet and outlet ports are each supported in the form of a straight line between a roller on each of said rotors.

2. A rotary pump according to claim 1, where each of said two rotors includes two rollers spaced apart on its respective rotor, said two rotors being rotated at the same speed in opposite directions. 

1. A rotary pump comprising: an oblong chamber having a long axis the opposite ends of which are semi-circular in section; an inlet port and an outlet port having a common axis perpendicular to the long axis of the oblong chamber; two rotors one on each side of said common axis; means for rotating said rotors in opposite directions; at least two equally spaced rollers carried by each of said rotors; and a single closed-loop belt of a width equal to that of the chamber disposed within but unattached to said chamber; said closed-loop belt being supported by said rollers and tightly enclosing same while under tension; whereby rotation of the rotors causes the rollers continuously to press the outer surface of the belt against the chAmber peripheral wall along semi-circular end sections of the chamber, while the two runs of the belt intersecting said common axis between the inlet and outlet ports are each supported in the form of a straight line between a roller on each of said rotors.
 2. A rotary pump according to claim 1, where each of said two rotors includes two rollers spaced 180* apart on its respective rotor, said two rotors being rotated at the same speed in opposite directions. 